Some comments: I was surprised by the CERA rankings. They show that Charlie O'Brien wasn't as statistically good a defensive catcher as the reputayion for being one that kept him in the majors for so long. He uses certain batter stats to calculate the effectiveness of a catcher, but I didn't notice ERA. IIRC when Piazza came to the Mets it was reported that the ERA of his staffs in LA had about a haf a run lower ERA when pitching to Mike than it was when the same pitchers threw to his replacement receivers. I would have liked to have seen a similar comparison with the catchers who were rated highly using CERA. Two of the lower rated catchers, Parrish and Stanley were moved to other positions (1B, DH). I guess their managers didn't need the CERA to know that they weren't that good defensively. The list of guys who started out as catchers and were moved before they could amass the number of games to qualify for his evaluation includes Rico Carty, Joe Torre, Dale Murphy (what is it with those fucking Braves?) and Craig Biggio. When considering popups, are catchers rated on "range factor" too? It is important. While, as was noted, few catchers miss many popups. But there is a disparity in distances they have to run in vatious ballparks. it used to be over 50 feet to the backstop in Forbes Field (Pittsburgh) and the foul territory in Oakland is huge. Getting to a popup is therefor more important than being able to catch it. Range factor would be informative here. As for being able to throw out runners, some catchers had the misfortune to be the receiver for staffs that were terrible at holding runners close or were breaking ball pitchers. If you have three starters who allow the runner an additional first step or two, or the ball doesn't get to them quickly, they probably won't have a high success rate, no matter how good their arm. Finally, wrt the comment above about backing up first on infield grounders - maybe Mike was running down the line just as hard as Grote. It (to paraphrase a Tom Seaver line) just took him longer to get there. Later